1. Field of the Invention
The present invention generally relates to a technique for controlling an external device, and more particularly, to a method and apparatus for controlling an external device such as a digital recording/reproduction device via a digital data bus by using auto-play and/or auto-pause functions.
2. Background Information
A digital data bus can be utilized for transmitting digital data in a network among digital devices, such as television signal receivers, personal computers (PCs), display devices, digital video cassette recorders (DVCRs), digital versatile disk (DVD) players, audio/video hard disk drives (AVHDDs), direct broadcast satellite (DBS) receivers, home control devices (e.g., security systems, temperature control devices, etc.), and/or other devices. A digital data bus is typically compliant with a particular standard or specification. An example of a wired digital bus standard includes the Institute for Electrical and Electronic Engineers (IEEE) 1394 High Performance Serial Bus standard, which is well known in the art. Wireless digital bus standards, such as Hiperlan2, are also known in the art.
In a digital bus network, certain problems may occur when one device, such as a television signal receiver, disconnects from an external device in the network, such as an AVHDD, and later re-establishes the connection with the external device. Such a disconnection and connection in a digital bus network may involve a specific signal protocol (e.g., disconnect request—disconnect response, connect request—connect response, etc.), and may occur when a user causes a network device to switch from one input to another input. For example, problems may occur in that when the connection with the external device is re-established, the external device may restart playing the track it was playing at the time of disconnection from the beginning. It is likewise problematic if the external device continues to play after the disconnection is made. In particular, both of the foregoing situations are generally undesirable since users are unable to continue playing a track from its then-current point at the time of disconnection, and must either advance and or reverse within the track to find the exact point where they left off. This process can be imprecise, inconvenient, time consuming and frustrating for users.
One approach for addressing the foregoing problems is for devices to store and maintain a list of all other network devices that indicates the last state such network devices are in at the time of disconnection. This approach, however, is not optimal since it may be rather complex to implement, and also consumes valuable memory capacity of a device. Another approach for addressing the foregoing problems is to maintain a connection with a network device when switching away from that device, This approach is likewise not optimal since maintaining a connection with a device in a digital bus network may lead that device to falsely believe that it has an avenue to communicate with the other connected device.
Other problems may also occur in a digital bus network as the result of a power interruption (e.g., device turned off, device unplugged, etc.). For example, if a device is connected to another network device at the time of a power interruption, when power to the device is restored, the device may be automatically switched to a non-network input (e.g., antenna input), and away from the network device. This may be inconvenient in that it requires users to manually switch back to the network device.
The present invention addresses the foregoing and/or other problems by providing a method and apparatus for controlling an external device such as a digital. recording/reproduction device via a digital data bus using auto-play and or auto-pause functions.